RainJets hydroejector - cleaning tanks - storage of stormwater or wastewater



The RainJet is a hydroejector designed to automatically clean tanks used for temporary storage of storm- or wastewater so odour problems are avoided and storage capacity is maintained.

The RainJet keeps on flushing until the tank is completely empty and all matters are back in the sewer system. It uses the detained water already in the tank and hence does not need an external source of fresh water.

The RainJet is made either as a water/water (WW) or water/air (WA) ejector

  • RainJet WW with greater flow for cleaning wider tanks
  • RainJet WA with longer reaching jet and mixed with air

The RainJet is made in complete stainless steel of AISI 304/DIN1.4301 or AISI 316/DIN 1.4401 and coupled to a  wastewater pump of the SE or S type.


No matter size and layout a customised solution of one or more RainJets can easily be designed to clean detention, equalisation, or stormwater tanks when used for storage of excess water in order to minimise the risk for:

  • Flooding or pollution of receiving waters if capacity of the sewer system is exceeded
  • Damage of biological processes at the WWTP if untreated industrial process water arrives
  • Disruption of purification processes at the WWTP due to hydraulic overload

Features and benefits

  • Available as water/water or water/air ejectors
  • RainJet WA available with a 2nd stage for extra thrust
  • Made completely in stainless steel for strength
  • Available with standard pumps in many motor sizes
  • Fitted with sturdy submersible wastewater pump of the SE and S type
  • Suite tanks of different size, depths and shape
  • Mixing and cleaning handled with same the unit
  • Large free passage – no clogging
  • Fixed or autocoupling connections suiting every type of installation
  • Pumps on autocoupling to make maintenance easier and more flexible


  • Available as water/water or water/air ejectors
  • Made completely in stainless steel for strength
  • Available with standard pumps in many motor sizes




A Wide Range (English) (Product brochure)

A Wide Range

Grundfosliterature-1322.pdf (6 MB)



Information and Advice

Grundfos is a world-wide provider of pumps and related systems. We have a highly educated and trained staff of service engineers who will be able to support you during the installation phase of the pump or the solution.  Grundfos supplies high-quality products, but to maintain a long life of the product or the system we have many years of experience in different kinds of installations and have achieved good practice in installation techniques.

We will be able to support you with the following elements:

  • Information about a proper protection of our pump.
  • Physical placement of the pump to maintain necessary service/repair.
  • Physical placement of the pump to maintain proper operation.
  • Correct cabling to fulfil the requirements of good practice and Electro Magnetic Compliance

Do not hesitate to contact your local Grundfos company to obtain full support for your new installation.



To achieve optimum performance and operating condition it is very important that the Product/System is set up and adjusted correctly from the start. The knowledge from the Grundfos Service technician and the use of Grundfos specific service tools to adjust the performance of the pump guarantee that the customer can be sure that that the highest efficiency and proper operation is achieved. Commissioning of the pump is recommended for the following applications:

  • If the pumps are controlled by a frequency converter .
  • If the pump system is operating in large systems e.g. Building Management Systems
  • If the user wants to be trained in proper operation of the pump.  
  •  If the pump must not be a missing link in an important production/application facility. 
  •  Where the setup is crucial for proper life of the Grundfos product, e.g. water treatment applications, commissioning is not only recommended but it is required.
  • Where safety is an issue e.g. disinfection system.

The commissioning is performed in a step by step procedure and the outcome will be a report of the settings of the pump.

Do not hesitate to contact your local Grundfos company to arrange commissioning of you new installed Grundfos product.


Recommended Spare Parts

Even though the Grundfos strategy is to supply the best pump solutions for our customers, long operation will result in wear and tear of some of the components in the construction in specific situations. If a short operating downtime is a demand or if the pump is installed in inaccessible areas where delivery of service parts may take a long time, it is recommended to have a small stock of recommended service parts.

Do not hesitate to contact your local Grundfos company to obtain information about recommended spare parts or service kits for your Grundfos product.



Service Agreement

A Grundfos Service Agreement ensures efficient and uninterrupted operation of your pumps system and gives you access to Grundfos Service Centres and authorised Service Partners worldwide, 24 hours a day.

Prevention is better and more cost effective than cure

Once you have purchased your pump, you want it functioning efficiently and reliably, and a formal Service Agreement with Grundfos gives you peace of mind. It also makes sound economic sense, giving you a firm overview of your maintenance budget and access to substantial discounts.

Let us carry out scheduled maintenance visits to prevent downtime.
You will be serviced by specially trained staff at all times.

The cost-effective choice

Well-maintained pumps can reduce your energy consumption by up to 50% and in a series of pumps working together one faulty pump can affect all the others. A Grundfos Service Agreement keeps your total cost of owning a pump to a minimum, because our careful consideration of the Life- Cycle Cost of all our products means that we have control of the real costs of ownership of our pumps.

Signing up for a Service Agreement and letting our highly skilled service technicians service your pumps is your safeguard against unforeseen expenditure. Regular servicing and maintenance of your pumps ensures that they are working with optimum efficiency.

Repair and Maintenance

Grundfos Service will maintain and repair your pumps and our service professionals can advise you on efficiency issues, offering suggestions for saving money in the long term.

Repair and maintenance of your existing pumps system
Of course, you can always call Grundfos for repair and maintenance of pumps you have purchased from us. Grundfos can repair your pumps to the same specifications as new pumps, but it is important to remember that an upgrade or even a replacement pump can be cheaper than repair in the long term. See Upgrades and Replacement for how this makes good business sense.

Effective service – wherever you are
Grundfos Service is always close by. Together with our local authorised service partners, we offer worldwide service, and help from qualified pump professionals is never far away, whether you need immediate assistance or you are interested in hearing about your savings possibilities.



Grundfos Remote Management is a cost-effective, secure and reliable way to monitor and manage pump installations from an Internet PC at a very low price.

Connecting pumps and people
With a secure and reliable remote management system, you can monitor and manage your pump systems from an Internet PC at a very low price.

Grundfos Remote Management is a cost-effective and straightforward way to monitor and manage pump installations in commercial buildings and in water supply and wastewater infrastructure. It reduces the need for onsite inspections, and in the event of an alarm or warning, the relevant people are notified directly.

Compared with mobile phone-based monitoring, the system offers a wider range of benefits and functionalities. For those who do not require remote process automation, Grundfos Remote Management is the ideal solution for monitoring and remote control as opposed to traditional SCADA (Supervisory Control and Data Acquisition) systems. Initial investment is minimal, and a fixed low fee covers data traffic, hosting costs and system support, including back-up of all data.

Efficient alarm management
Via its on-call schedule, this new telemetry system ensures that alarms from onsite controllers go directly to the relevant people. From a PC anywhere, the system manager can log on and plan who is to receive alarm messages from each installation at any given time of the day. Managers can plan years ahead and easily handle daily exceptions to the schedule.

Optimize service and maintenance
Changes in pump performance can be tracked using trend graphs automatically generated by the system. This can give an indication of wear or damage in the installation, and service and maintenance can be planned accordingly.

The communication interface (the CIU271 modem) enables data transmission via GPRS/SMS from your Grundfos pumps and controllers. The built-in multi-purpose I/O board allows you to connect sensors and switches.Grundfos Pump Audit is our replacement analysis and is a complete diagnostic tool, focusing on your facility, your system’s energy efficiency, your pumping solutions total Life Cycle Costs, and detailed recommendations for replacement and pay-back time.




The purpose of CAPS is to offer a complete tool that contains an extensive catalogue of Grundfos products and a sizing programme to select the most suitable pump for your application.

On top of that there is a comprehensive pump replacement function for central heating circulating, hot water pumps and the wastewater S pumps and the possibility of producing professional quotations including curves, drawings, quotation texts, wiring diagrams etc.

Last but not least the programme contains the instruction and operating manuals for nearly all pumps of Grundfos in multiple languages. Service drawings, exploded views and parts lists are available for all sewage products as well as several other pump types.

CAPS is available in two versions: WinCAPS is available on a CD-ROM and the online version called WebCAPS is available at the Grundfos website - www.grundfos.com. Additional features in WebCAPS include CAD Drawings and Literature.

Spare parts

Spare Parts

Spare Parts
BE Responsible is one of our key drivers in Grundfos. It is therefore essential to us, that our pumps are developed with a low energy consumption and the highest possible performance throughout their life. Therefore, Grundfos Service Offerings including spare parts and replacement kits are defined already in the development phase.
Customized service offerings, online ordering and rapid response distribution centres ensure you to have the parts when you need them.

Recommended Spare Parts List.
The list specifies the parts you should have on site to service your pumps. These recommendations can be found at the product site in our WEB Caps tool.

Specially Designed Service Kits.
Service Kits include everything you need for a specific maintenance or repair task, including instructions for dismantling, replacement and reassembly.

24-hour Spare Part Delivery Service.
To be extra sure you do not have to wait, we can set aside a stock of your operation critical spare parts. This will make them available for you, whenever you need them.

10-year Guarantee
Spare parts for the Grundfos pump you buy today will still be available for 10 years - this is our guarantee to you.

Service Online Tool
From a PC anywhere you have 24-hour access to our online tool WebCaps. All the technical documentation and information you need to service your pumps is immediately available to you anytime:

  • Service Instructions
  • Step-by-step service videos
  • Interactive exploded views
  • Sectional drawings
Sales office

Contact us

Select country to contact your local sales company


01525 850000


Grundfos Pumps Ltd.
Grovebury Road
Leighton Buzzard
Beds. LU7 4TL

Service center

Contact us

Select country to contact your local service center


01942 263628


Grundfos Service Ltd.
Beswick House
Greenfold Way
Leigh WN7 3XJ